Agricultural toolbar apparatus, systems and methods

ABSTRACT

Systems, methods and apparatus for shifting weight between a tractor and toolbar and between sections of the toolbar, for controlling operative height of a toolbar and sections of a toolbar and for folding a toolbar between a work position and a transport position. A ground engaging wheel and an actuator are coupled to the toolbar. In one embodiment, a fluid control system is responsive to a command signal to modify the actuator pressure such that the actuator pressure corresponds to a desired pressure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National State of International Application No.PCT/US2012/040756, filed Jun. 4, 2012 which claims the benefit of U.S.Provisional Application No. 61/493,158, filed Jun. 3, 2011.

BACKGROUND

Agricultural toolbars such as planters have become larger and heavier asfarming operations have become larger. Thus growers have increasinglyrecognized the potential to improve yield by reducing compaction damageby such toolbars. As a result, there is a need in the art for systems,apparatus and methods of shifting weight between the toolbar and thetractor and between sections of the toolbar in order to reduce agronomicdamage from compaction. Additionally, the time pressure in performingplanting operations has created a need in the art for effective andefficient systems, apparatus and methods of folding agriculturaltoolbars between field position and a planting position, and especiallyfor toolbars having a field position in which turns and changes intopography are effectively negotiated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a generally rearward perspective view of an embodiment of atoolbar in a transport position.

FIG. 1B is a generally rearward perspective view of the toolbar of FIG.1A in a work position.

FIG. 1C is a generally rearward perspective view of the toolbar of FIG.1A in an intermediate position.

FIG. 2A is a top view of the toolbar of FIG. 1A in a transport position.

FIG. 2B is a top view of the toolbar of FIG. 1A in a work position.

FIG. 2C is a top view of the toolbar of FIG. 1A in an intermediateposition.

FIG. 3A is a side elevation view of the toolbar FIG. 1A in a transportposition.

FIG. 3B is a side elevation view of the toolbar of FIG. 1A in a workposition.

FIG. 4A is a generally rearward perspective view of an embodiment of atoolbar mount.

FIG. 4B is a rear elevation view of the toolbar mount of FIG. 4A.

FIG. 4C is a generally forward perspective view of the toolbar mount ofFIG. 4A.

FIG. 5A is a partial top view of the folding frame of the toolbar ofFIG. 1A.

FIG. 5B is a generally rearward partial perspective view of the foldingframe of the toolbar of FIG. 1A.

FIG. 6A is partial top view of the toolbar of FIG. 1A in a left-turnwork position.

FIG. 6B is a partial top view of the toolbar of FIG. 1A in a right-turnwork position.

FIG. 7A is a side elevation view of a conventional three-point hitch.

FIG. 7B is a side elevation view of a toolbar mount in combination witha modified three-point hitch.

FIG. 7C is a side elevation view of a modified toolbar mount incombination with a three-point hitch of FIG. 7A.

FIG. 8A is a partial perspective view of the folding frame joint of thetoolbar of FIG. 1A.

FIG. 8B is a partial top view of the folding frame joint of the toolbarof FIG. 1A.

FIG. 8C is a partial cross-sectional view of the folding frame joint ofthe toolbar of FIG. 1A along the section A-A indicated in FIGS. 8A and8B.

FIG. 9A is a perspective view of the transport hitch of the toolbar ofFIG. 1A.

FIG. 9B is a top view of the transport hitch of the toolbar of FIG. 1A.

FIG. 9C is a side elevation view of the transport hitch of the toolbarof FIG. 1A.

FIG. 10 is a rear elevation view of the transport latch of the toolbarof FIG. 1A.

FIG. 11 illustrates an embodiment of a process for folding a toolbarfrom a work position to a transport position.

FIG. 12 illustrates an embodiment of a process for folding a toolbarfrom a transport position to a work position.

FIG. 13 schematically illustrates an embodiment of a toolbar controlsystem.

FIG. 14 is a side elevation view of an embodiment of a planter row unit.

FIG. 15 is a schematic illustration of a side elevation view of aportion of a tractor and an embodiment of a planting implement includinga planter row unit and a lift assist wheel.

FIG. 16 illustrates an embodiment of a process for transferring weightbetween a tractor and a toolbar.

FIG. 17 illustrates another embodiment of a process for transferringweight between a tractor and a toolbar.

FIG. 18 illustrates an embodiment of a process for controlling theheight of a toolbar.

FIG. 19A schematically illustrates a toolbar height control scenario.

FIG. 19B schematically illustrates another toolbar height controlscenario.

FIG. 19C schematically illustrates another toolbar height controlscenario.

FIG. 20 illustrates an embodiment of a toolbar height control lookuptable.

FIG. 21 illustrates another embodiment of a process for controlling theheight of a toolbar.

FIG. 22 illustrates an embodiment of a center section height controlloop and an embodiment of a wing section height control loop.

FIG. 23 illustrates an embodiment of a combined height control loop fora center section and a wing section.

FIG. 24 illustrates another embodiment of a process for transferringweight between a tractor and a toolbar.

FIG. 25 illustrates another embodiment of a process for transferringweight between a tractor and a toolbar based on an operator command.

DESCRIPTION

Overview

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIGS. 1Aand 1B are perspective views of an agricultural toolbar 10 in atransport position and a work position, respectively. FIG. 1C is aperspective view of an intermediate position between the work andtransport positions. Toolbar 10 includes a mount 200, a folding frame400, and a rear section 500. Mount 200 is attached to a tractor or otherdraft vehicle. In the work position, rear section 500 is attached to themount 200 by a work hitch 300. In the transport position, the foldingframe 400 is attached to the mount 200 at a transport hitch 490. Inoperation, the toolbar 10 is moved from the transport position to thework position by collapsing the folding frame 400 and attaching the rearsection 500 to the work hitch 300. The toolbar 10 is moved from the workposition to the transport position by detaching the rear section 500from the work hitch 300 and unfolding the folding frame 400. ComparingFIGS. 1A and 1B, it should be appreciated that in the transportposition, the transverse profile of toolbar 10 is substantially narrowerthan in the work position. The greatest transverse width of the toolbar10 in the transport position, including any attached tools, ispreferably within the allowable width permitted by applicableregulations for over-the-road transport.

Ground-Engaging Tools and Wheels

As best illustrated in FIG. 5B, tools may be fixed to a center bar 520of the rear section 500 and to wing sections 410 of the folding frame400 by mounting hole arrangements 440, or by U-bolts or other mountingstructure known in the art. The tools may comprise planter row units(such as disclosed in FIG. 1 of Applicant's co-pending U.S. patentapplication Ser. No. 12/679,710, the disclosure of which is herebyincorporated herein in its entirety by reference), seed drill row units,soil tillage tools, or other crop input units or ground-working toolsknown in the art. Lift-assist wheel assemblies 1500 (not shown in FIG.5B, functionally similar to the lift-assist wheel assembly 1500illustrated in FIG. 15) are preferably mounted to mounting brackets 540mounted to the center bar 520. Mounting brackets 540 preferably includemounting hole arrangements for the installation of the lift assist wheelassemblies. Wing wheel assemblies (not shown) such as those generallydesignated by reference numerals 56 and 60 in U.S. Pat. No. 7,469,648,the disclosure of which is hereby incorporated herein in its entirety byreference, may also be mounted at mounting hole arrangements 440 at ornear the outboard ends of wing sections 410. It should be appreciatedthat in some embodiments and operating modes, such tools and wheelsengage the ground, imposing generally vertical loads on the center bar520 and the wing sections 410.

Lift assist wheels 1550 (FIG. 15) may be mounted in a castering fashion(as illustrated in U.S. Pat. No. 4,026,365, the disclosure of which isincorporated herein in its entirety by reference) such that each liftassist wheel may pivot about a generally vertical axis during operation.It should be appreciated in light of this disclosure that such casteringlift assist wheels 1550 permit turning of the toolbar 10 around smallerradii.

Toolbar Components

Referring to FIGS. 2A and 2B, the toolbar 10 is illustrated from a topview in its transport position and working position, respectively. FIG.2C is a top view of the toolbar 10 in an intermediate position betweenthe transport and working positions. Folding frame 400 includestransport hitch 490, inboard draft bars 405, outboard draft bars 415,the wing sections 410 and pivot bars 420. The inboard draft bars 405 arepivotally mounted to the transport hitch 490 for pivoting about agenerally vertical axis. The outboard draft bars 415 are pivotallymounted at a first end to the inboard draft bars 405 for pivoting abouta generally horizontal axis. Relative pivoting of the draft bars 405,415is preferably selectively lockable as described later herein. Theoutboard draft bars 415 are pivotally mounted at a second end to wingsections 410 for pivoting about a generally vertical axis. Wing sections410 are pivotally mounted to pivot bars 420 for pivoting about agenerally horizontal axis. The rear section 500 includes the center bar520, to which the pivot bars 420 of the folding frame 400 are pivotallymounted for pivoting about a generally vertical axis. In operation, thefolding frame 400 is preferably reconfigured from the transport positionto the work position by pivoting the wing sections 410 and the draftbars 405,415 in an outboard direction until the wing sections are insubstantially parallel or near-parallel alignment along a directionsubstantially transverse to the direction of travel. The folding frame400 is preferably unfolded from the work position to the transportposition by pivoting the wing sections 410 and the draft bars 405,415 inan inboard direction until the wing sections are in generally parallelor near-parallel alignment along a direction substantially parallel tothe direction of travel.

Wing fold cylinders 424 are pivotally mounted at a first end to centerbar 520 and at a second end to pivot bar 420. Wing fold cylinders 424are preferably dual-acting hydraulic cylinders capable of collapsing andunfolding the folding frame 400 as described herein by pivoting the wingsections 410 relative to center bar 520. The fluid control system 1330preferably controls the wing fold cylinders 424 in a flow control mode,e.g., using a flow control valve 1334 incorporated in the fluid controlsystem 1330.

It should be appreciated that where the toolbar 10 includessubstantially equivalent or mirror-image left- and right-handcomponents, the left-hand components generally correspond to a referencenumeral with the suffix “−1” and the right-hand components generallycorrespond to the same reference numeral with the suffix “−2.” Both theleft- and right-hand components may be collectively referenced herein bythe reference numeral without either suffix.

Folding Frame Components

The transport hitch 490 is illustrated in more detail in FIGS. 9A-9C.Each inboard draft bar 405 is mounted to a respective clevis 491. Thedevises 491 are both pivotally coupled to a pin 498. Pin 498 isrotatably housed within an inner surface of a pin boss 493. A hitch bar495 is pivotally coupled to an outer surface of the pin boss 493.Specifically, the hitch bar 495 preferably includes upper and lowersurfaces having apertures that pivotally engage the pin boss 493. Theupper and lower surfaces of hitch bar 495 also include tips 496 whichextend between the devises 491, limiting the relative rotation of theinboard draft bars 405 to the extreme position best viewed in FIG. 9B.Bosses 494 are mounted to the pin 498 and hold the devises 491 invertically spaced relation. A pin flag 499 is preferably mounted to anupper surface of pin 498 and attached to clevis 491-1, preventing pin498 from rotating relative to clevis 491-1. A lunette ring 492 ismounted to hitch bar 495.

As best viewed in FIGS. 3A and 3B, lunette ring 492 engages a pintlehitch 250, which is mounted to the mount 200. Thus in the transportposition, mount 200 draws the toolbar 10 by the lunette ring 492. Itshould be appreciated that in the transport position, the couplingbetween the pintle hitch 250 and lunette ring 492 allows pivotingbetween the mount 200 and the folding frame 400 about a generallyvertical axis, but also allows the mount and folding frame to pivotrelative to one another about a generally horizontal axis.

The right-hand components of the foldable frame 400 are illustrated inmore detail in the work position in FIGS. 5A and 5B. The inboard draftbar 405 and outboard draft bar 415 are joined at a joint 433. Joint 433constrains the draft bars 405,415 to pivot relative to one another abouta substantially horizontal axis 417. The pivot bar 420 and the wingsection 410 are joined at a joint 423. The joint 423 constrains the wingsection 410 and the pivot bar 420 to pivot relative to one another abouta substantially horizontal axis 412. Axis 417 and axis 412 arepreferably substantially parallel to one another. Moreover, axis 417 andaxis 412 are preferably substantially collinear with one another.Because axes 417,412 are substantially collinear, the wing section 410is allowed to pivot about joint 423 in the work position withoutinterference. Thus as the toolbar 10 traverses the field, the wingsection 410 may be raised or lowered relative to center bar 520 inresponse to changes in terrain.

Joint 433 is illustrated in more detail in FIGS. 8A-8C, in which a latchhook 434 and an actuator 432 (both described herein with respect to FIG.5B) are not shown for clarity. As best seen in the cross-sectional viewof FIG. 8C, joint 433 includes a pin 450, an inboard boss 458, andoutboard bosses 455,456. Pin 450 is pivotally mounted within bosses455,456,458. Inboard draft bar 405 includes hinge plates 465,466 whichare preferably pivotally coupled to inboard boss 458. Outboard draft bar415 is coupled to outboard bosses 455,456. Outboard draft bar 415 alsoincludes hinge plates 461,462 which are coupled to the outboard bosses456,455, respectively. A pin flag 468 is preferably mounted to one endof pin 450 and to hinge plate 461, preventing pin 450 from rotatingrelative to outboard draft bar 415.

It should be appreciated that pin 450 defines the axis 417 illustratedin FIG. 5A. Thus it is the orientation and position of pin 450 withrespect to axis 412 that allows the outboard draft bar 415 and the wingsection 410 to pivot simultaneously without interference. For example,if embodiments in which draft bars 405,415 are substantially parallelwith wing section 410 and pivot bar 420 in the work position, pin 450 ispreferably substantially co-axial with bosses 455,456,458.

When toolbar 10 is in the transport position or reconfiguring from thework position to the transport position, joints 423 or joints 433 arepreferably locked to prevent the folding frame 400 from collapsing.Joint 423 may be locked by preventing extension or retraction of anactuator 428, described elsewhere herein, using an external lockingmechanism (not shown). Joint 433 is preferably locked using latch hook434 (best seen in FIG. 5B, in which actuator 428 is not shown forclarity). Latch hook 434 is pivotally mounted to the inboard draft bar405 and releasably latches outboard draft bar 415. In transport, thelatch hook 434 is generally in compression preventing joint 433 frommoving downward. However, if loads acting on joint 433 bias joint 433upward, the latch hook 434 is placed in tension. Latch hook 434 ispreferably selectively engaged and disengaged using an actuator 432.Actuator 432 is pivotally mounted at a first end to the inboard draftbar 405 and at a second end to the latch hook 434. Actuator 434 ispreferably a dual-acting hydraulic cylinder. Extension of the actuator432 disengages the latch hook 434, allowing the draft bars 405,415 topivot relative to one another. Retraction of the actuator 432 engagesthe latch hook 434, preventing the draft bars 405,415 from pivotingrelative to one another.

Continuing to refer to FIG. 5B, pivot bar 420 is pivotally mounted tocenter bar 520 by a clevis 422. Clevis 422 is mounted to center bar 520at a pin 421. Pin 421 constrains the pivot bar 420 to rotate withrespect to center bar 520 about a substantially vertical axis. Asillustrated in FIGS. 1A and 2A, in the transport position, clevis 422engages center bar 520 such that the pivot bars 420 do not pivotrelative to center bar 520.

It should be appreciated that relatively large stresses may be imposedon pin 421 as varying vertical loads are imposed on center bar 520 andpivot bar 420. Thus the toolbar 10 preferably includes features thatpartially relieve these stresses from the pin 421. In the work position,referring to FIG. 5B, pivot bar 420 preferably includes a stop pocket426 and center section 520 preferably includes a roller 525. Whenreconfiguring from the transport position to the work position, theroller 525 preferably engages the stop pocket 426. Stop pocket 426preferably includes upper and lower chamfered surfaces to guide theroller 525 into the stop pocket. If the center bar and pivot bar pivotvertically relative to one another beyond a threshold amount, the roller525 contacts the stop pocket 426 such that a portion of the deflectionload shifts to the stop pocket and roller, reducing the load on the pin421. In the transport position, as best seen in FIG. 1A, each clevis 422preferably engages the center bar 520 such that the load required tomaintain the relative position of the pivot bar 420 and the center baris shared between the pin 421 and the clevis.

In the work position, center bar 520 and wing section 410 may be pivotedabout joint 423 using an actuator 428. Actuator 428 is pivotally mountedat a proximal end to pivot bar 420 and at a distal end to wing section410. Actuator 428 is preferably a dual-acting hydraulic cylinder. Thefluid control system 1330 preferably controls the actuator 428 in a flowcontrol mode, e.g., using a flow control valve 1334 incorporated in thefluid control system 1330. Thus the fluid control system is operable tomodify the position (i.e., the degree of extension) of the wing sectionactuator 428. Extension of actuator 428 will pivot the wing section 410downward relative to center bar 520. Likewise, retraction of actuator428 will pivot the wing section 410 upward relative to center bar 520.It should be appreciated that the mounting positions of the head end androd end of actuator 428 may be reversed in other embodiments.

Work Hitch

The work hitch 300 selectively retains the toolbar 10 in the workposition. Referring to the transport and work position side views ofFIGS. 3A and 3B, rear section 500 includes a saddle 510. Saddle 510includes upper kingpin 512-1 and lower kingpin 512-2. Mount 200 includesupper kingpin latch 212-1 and lower kingpin latch 212-2. When thetoolbar 10 reconfigures to the work position, the kingpin latches 212preferably engage the kingpins 512. As best illustrated in theperspective view of FIG. 4A, each kingpin latch 212 includes a pair ofpivot plates 216, each having a slot at a rearward end. A latch plate214 is pivotally mounted between each pair of pivot plates 216. Anactuator 222 is pivotally connected at a forward end to the mount 200and pivotally connected at a rearward end to the latch plate 214. Whenthe toolbar 10 reconfigures from the transport position to the workposition, the kingpins 512 are received within the slots in pivot plates216. Once toolbar 10 is fully in the work position, the actuators 222preferably retract, rotating the latch plates 214 and securing thekingpins 512, thus retaining the toolbar 10 in the work position as thetractor moves forward. Before the toolbar 10 reconfigures from workposition to the transport position, the actuators 222 preferably extend,rotating the latches 214 to allow the kingpins 512 to move rearwardlyfrom the slots in pivot plates 216. It should be appreciated that otherapparatus and methods for securing the toolbar 10 in the work positionmay be used in other embodiments. For example, the latch plates 250 mayinclude a spring-loaded hook portion allowing the kingpins 512 to enterthe pivot plates 216 but preventing them from withdrawing until thelatch plates are rotated to disengage the kingpin latches 212.

As best illustrated in FIGS. 3A and 3B, saddle 510 extends rearward ofcenter bar 520 and preferably includes mounting structure for towing atrailing cart such as that disclosed in U.S. Pat. No. 5,485,797.

As best illustrated in FIGS. 6A and 6B, the work hitch 300 preferablyallows the frame 400 to pivot about the kingpins 512 while in the workposition. Turning to FIG. 3B, in the work position, pintle hitch 250 andlunette ring 492 are disengaged such that horizontal forces areprimarily imparted from the mount 200 to the frame 400 through thekingpins 512. Thus when latched in the work position, upper kingpin512-1 and lower kingpin 512-2 define a generally vertical axis ofrotation about which the mount 200 and frame 400 may pivot relative toone another during operation. Thus although the mount 200 is integrallymounted to the tractor, the tractor may turn about a certain minimumradius without turning the frame 400. Returning to FIGS. 6A and 6B, itshould be appreciated that if the tractor turns about the minimumradius, the torque tube 205 (described herein with respect to FIG. 4A)will contact one of the inboard draft bars 405. Thus in a preferredembodiment, either the inboard draft bars 405 or the torque tube 205 areprovided with resilient stops 280 as illustrated in FIGS. 6A and 6B. Thestops 280 may comprise pads made of resilient material such as rubber,or may comprise any apparatus configured to prevent damage to thetoolbar 10. It should be appreciated that in other embodiments, thetorque tube may be shortened horizontally in order to allow the tractorto turn freely about smaller radii.

The work hitch 300 preferably transfers vertical loads from the mount200 to the folding frame 400 and thus to the tools mounted to the centerbar 520 and wing sections 410. Returning to FIGS. 3A and 3B, saddle 510includes a weight transfer plate 515 having upper and lower chamferededges. When the toolbar 10 reconfigures the work position, the plate 515passes between two thrust rollers 215 (best viewed in FIG. 4B) pivotallymounted to the mount 200. A lower thrust roller 215-1 is preferablydisposed to rollingly contact the lower chamfered surface of the plate515. An upper thrust roller 215-2 is preferably disposed to rollinglycontact the upper chamfered surface of the plate 515. The upper andlower chamfered surfaces of the plate 515 preferably lie 45 degrees froma vertical axis, while the upper and lower thrust rollers 515 arepreferably angularly offset by 90 degrees. It should be appreciated thatother configurations of the plate and thrust rollers would also allowtransmission of vertical loads between the mount 200 and the frame 400.

Net downward forces imposed on the mount 200 may be imparted to theframe 400 through the contact surface between the upper thrust roller215-2 and the upper chamfered surface of the plate 515. Net upwardforces imposed on the mount 200 may be imparted to the frame 400 throughthe contact surface between the lower thrust roller 215-1 and the lowerchamfered surface of the plate 515.

As best viewed in FIG. 2A, the chamfered surfaces of the weight transferplate 515 are preferably curved about a rearward generally verticalaxis. Thus when the toolbar 10 is in the work position, the mount 200may rotate about the kingpins 512 (e.g., to the positions shown in FIGS.6A and 6B) while the plate 515 remains disposed between the upper andlower thrust rollers 215.

Mount

The mount 200 is illustrated in further detail in FIGS. 3B and 4A-4C.Pintle hitch 250 is mounted to a torque tube 205. Side plates 219 aremounted in transversely spaced apart relation to the torque tube 205. Ahitch bar 242 is mounted to the side plates 219. A mast 210 is mountedto the torque tube 205, preferably disposed between and substantiallyequidistant from the side plates 219. Thrust rollers 215, kingpinlatches 212, and actuators 222 are coupled to mast 210, which extendsboth above and below the torque tube 205. A top link 220 is pivotallycoupled to mast 210 at a joint 221. A mount cylinder 230 is pivotallycoupled at a first end to the mast 210 at a joint 217. Mount cylinder230 is pivotally coupled at a second end to the top link 220 at a joint218. Mount cylinder 230 is preferably a dual-acting hydraulic cylinder.It should be appreciated in light of the instant disclosure that themount cylinder 230 comprises a weight transfer actuator operable totransfer weight between the tractor and the toolbar 10. Put otherwise,the mount cylinder 230 transmits vertical forces between the tractor andthe toolbar 10.

The mount 200 is preferably configured to be mounted to a three-pointhitch. A prior art three-point hitch 600, similar to that described inU.S. Pat. No. 7,861,794, the disclosure of which is hereby incorporatedherein in its entirety by reference, is illustrated in FIG. 7A. Thehitch 600 includes a pair of transversely spaced draft links 610, a toplink 620 disposed centrally above the draft links, a pair of struts 630and associated draft link cylinders 640 configured to raise and lowerthe draft links. The combination of the mount 200 and the hitch 600 isillustrated in FIG. 7B. To attach mount 200 to hitch 600, the top link620 is preferably removed and the top link 220 is attached at a joint224. Struts 630 are preferably disengaged from draft links 610 andpreferably removed. Draft links 610 are then pivotally coupled to hitchbar 242.

In operation, the mount cylinder 230 may be retracted to raise thetoolbar 10 relative to the tractor, or extended to lower the toolbarrelative to the tractor.

Transport Latches

In a preferred embodiment illustrated in FIG. 10, the toolbar 10includes transport latches 480 to selectively hold the toolbar in thetransport position. Transport latch 480 includes a notched plate 413pivotally mounted to outboard draft bar 415 at a pin 414. An actuator416, preferably a dual-acting hydraulic cylinder, is mounted to the wingsection 410 and pivotally coupled to notched plate 413. In operation,the actuator 416 is actuated to raise and lower the notched plate 413 toselectively engage a pin 411 mounted to the wing section 410. When thenotched plate 413 is lowered to engage the pin 411, the wing section 410and outboard draft bar 415 are prevented from pivoting away from oneanother, holding the folding frame 400 in the transport position. In theillustrated embodiment, each transport latch 480 selectively latchesoutboard draft bar 415 to wing section 410, but it should be appreciatedthat similar embodiments of latch 480 could selectively hold the toolbarin the transport position, for example by latching inboard draft bar 405to the wing section 410, by latching inboard draft bar 405-1 to inboarddraft bar 405-2, or by latching outboard draft bar 415-1 to outboarddraft bar 415-2.

Tools

As described elsewhere herein, the tools mounted to toolbar 10 maycomprise planter row units. One such embodiment is illustrated in FIG.14, in which a planter row unit 1400 is mounted to wing section 410 by amounting bracket 13 installed to mounting hole arrangements 440 (FIG.5B). It should be appreciated that similar row units may be mounted tocenter bar 520.

Row unit 1400 is supported from the planter frame or toolbar 10 by aparallel arm linkage 14 extending between the wing section 410 and therow unit frame 16. A dead load indicated by arrow 18 represents the deadload of the entire row unit, including the mass of an opener diskassembly 20 (including opener discs 41 and gauge wheels 42), the frame16, a seed hopper 22, an insecticide hopper 24, a seed meter and seedtube, and the mass of any other attachments or devices supported by therow unit frame 16. In addition, live loads corresponding to the mass ofthe seed and insecticide stored within the hoppers 22,24 are representedby arrows 26 and 28, respectively.

A supplemental downforce 30 is also shown acting on the parallel arms14. The supplemental downforce 30 acts in a manner to either increase ordecrease the total or overall downforce on the row unit. Thesupplemental down force 30 is preferably applied by tool downforceactuator 32. To achieve a static load balance, the dead load 18, thelive loads 26,28 and the supplemental downforce 30 are resisted by thereactionary forces exerted by the soil against the opener disk (openerdisk load 38), the gauge wheels (the gauge wheel load 40) and closingwheels 34 (the closing wheel load 36).

As is well understood by those of ordinary skill in the art, a depthadjustment mechanism 44 is used to set the relative distance between thebottom of the opener disks 41 and the bottom surface of the gauge wheels42, thereby establishing the depth of penetration of the opener disks 41into the soil surface.

Toolbar Control System—Overview

A control system 1300 for controlling the toolbar 10 is illustrated inFIG. 13. The control system 1300 preferably includes a controller 1302,a fluid control system 1330, a folding actuator system 1320, a weighttransfer system 1310, a fluid power source 1335, an array of positionsensors 1340, a height control system 1350, a weight transfer sensor1355 (FIG. 15), an array of tool downforce actuators 32, and an array ofheight sensors 1360 (FIG. 14).

The controller 1302 is preferably in electrical communication with fluidcontrol system 1330. Fluid control system 1330 is in fluid communicationwith fluid power source 1335, folding actuator system 1320, weighttransfer system 1310, height control system 1350 and tool downforceactuators 32. Position sensors 1340 are preferably in electricalcommunication with the controller 1302. Height sensors 1360 arepreferably in electrical communication with the controller 1302. Theweight transfer sensor 1355 is preferably in electrical communicationwith the controller 1302.

Toolbar Control System—Controller

The controller 1302 preferably includes a CPU 1305, a memory 1309 and adisplay unit 1307 having a graphical user interface allowing a user toview information and enter commands. In a preferred embodiment, thecontroller 1302 is an implement monitor such as that disclosed inApplicant's co-pending U.S. patent application Ser. No. 13/292,384, thedisclosure of which is hereby incorporated herein in its entirety byreference.

Toolbar Control System—Tool Downforce Actuators

Each tool downforce actuator 32 (FIG. 14) is preferably configured toincrease or decrease the vertical force between the toolbar 10 and aground-engaging tool attached to toolbar 10.

In operation, the controller 1302 sends an individual command to thefluid control system 1330 in order to apply a desired vertical forcebetween each row unit 1400 and the toolbar 10. It should be appreciatedthat due to differences in soil conditions and other factors, thedesired and commanded vertical force may vary between tools and thevertical force applied to each tool may vary over time.

Toolbar Control System—Inputs

Each height sensor 1360 is preferably configured to generate anelectrical signal related to the height of a ground-engaging toolrelative to the toolbar 10. Referring to FIG. 14, the height sensor 1360may comprise a rotary potentiometer 1362 attached to a planter row unit1400. The potentiometer 1362 is preferably coupled to a follower arm1364 configured to rollingly contact an upper surface of a parallel arm14 and preferably biased downward against the parallel arm. Thus as therow unit 1400 moves up and down relative to the toolbar 10, the followerarm moves, causing a variation in an electrical signal generated by thepotentiometer 1362. In other embodiments, other suitable devices monitorthe relative vertical position of the row unit 1400 and toolbar 10. Forexample, a string potentiometer could be mounted to row unit 1400 havinga string attached to a parallel arm 14. In another embodiment, aposition sensor such as an LVDT displacement transducer could beincorporated with one or more tool downforce actuators 32; the length ofthe tool downforce actuator 32 may then be used to determine the angleof the parallel arms 14 relative to the toolbar 10. In still otherembodiments, as also illustrated in FIG. 14, a height sensor 1360mounted to the toolbar 10 (e.g., to wing section 410) may comprise aproximity sensor disposed to measure the distance between the toolbarand the ground at the lateral position of the height sensor.

The signal from each height sensor 1360 is related to theground-relative height of the portion of the toolbar 10 to which the rowunit incorporating the height sensor is mounted. (In embodiments where asuitable height sensor is coupled directly to the toolbar, the signal isrelated to the portion of the toolbar to which the height sensor iscoupled.) A height sensor 1360 may be incorporated in every row unit1400 mounted to toolbar 10. To accomplish the height control methoddescribed herein with respect to FIG. 18, it is beneficial toincorporate a height sensor 1360 on at least one row unit mounted tocenter bar 520 and on each at least one row unit mounted to each wingsection 410 because the wing sections 410 may flex relative to thecenter bar. However, it is preferable to have multiple height sensors1360 on each section of the bar (e.g., center bar 520 and each wingsection 410) due to potential variation in soil topography transverse tothe direction of travel. For example, if a single height sensor 1360 isused at the midpoint of wing section 410, the system may fail to detecta significant rise in soil elevation at the distal end of wing section410. In the most common variations in soil topography encountered duringfield working operations, the outboard end of one wing sectionencounters an area, often near the edge of a field. Put otherwise, it isrelatively rare for the toolbar to encounter a topographical featurethat affects only the height of the center bar or the inboard ends ofthe wing sections. Thus where a single height sensor 1360 isincorporated with a wing section row unit, it is preferably located nearthe distal end of the wing section.

As described herein with respect to FIG. 14, the tool downforce actuatormay comprise a cylinder configured to supply a supplemental downforce 30from toolbar 10 to a planter row unit 1400. In such an embodiment, thecommanded supplemental downforce 30 comprises an input to the toolbarcontrol system 1300 representing the vertical force transmitted betweentoolbar 10 and row unit 1400.

In the embodiment illustrated in FIG. 15, the weight transfer sensor1355 is preferably a suitable pressure sensor configured to measure thepressure in mount cylinder 230. In some of such embodiments, the weighttransfer sensor 1355 comprises a hydraulic pressure transducer such asthose manufactured by Link Engineering in Plymouth, Mich. The mountcylinder pressure comprises an input to the toolbar control system 1300related to the vertical force transmitted between the tractor and thetoolbar 10. In other embodiments, the weight transfer sensor 1355comprises a strain gauge mounted to the hitch 200 at a location bearingthe stress resulting from weight transfer between the tractor and thetoolbar (e.g., on the top link 220). As illustrated in FIG. 7C, in sometoolbar embodiments in which the toolbar is integrally mounted to thethree-point hitch by a modified hitch 200′, the weight transfer sensor1355 is preferably a fluid pressure sensor configured to generate asignal related to the pressure in the draft link cylinders 640. In suchembodiments, the weight transfer sensor 1355 is preferably in fluidcommunication with at least one of the draft link cylinders 640. Asdescribed elsewhere herein, the weight transfer sensor 1355 ispreferably in electrical communication with the controller 1302 forcommunicating a signal related to the pressure in draft link cylinders640.

The position sensors 1340 may comprise any suitable set of devices fordetermining the current position of the toolbar 10. In one embodiment,the position sensors 1340 may comprise external linear displacementtransducers incorporating Hall-effect sensors (such Model No. SLH100available from Penny & Giles in City of Industry, Calif.) configured togenerate an electrical signal related to the position of an actuator.Such sensors may be incorporated in the wing fold cylinders 424, mountcylinder 230, and wing section actuator 428, as well as other actuatorsdescribed herein. The controller 1302 may use position sensors 1340 todetermine whether the toolbar 10 is in specified configurationsappropriate for engaging and disengaging the latches described herein.It should be appreciated that in some embodiments, the position sensors1340 are eliminated and the operator enters commands to the controller1302 indicating when the toolbar 10 is in such configurations.

Toolbar Control System—Outputs

The folding actuator system 1320 includes the draft tube latch actuators432, wing fold cylinders 424, transport latch actuators 416, kingpinlatch actuators 212, and wing wheel actuators 1319 configured to raiseor lower one or more wing wheels.

The weight transfer system 1310 includes lift assist actuators 1317(FIG. 15) configured to raise or lower one or more lift assist wheelassemblies 1500 attached to the toolbar.

The height control system 1350 includes the mount cylinder 230 and wingsection actuators 428.

Folding Methods

In operation, the toolbar 10 preferably reconfigures from the workposition to the transport position according to a process illustrated inFIG. 11. At step 1105, the mount cylinder 230 is preferably fullyretracted to raise the toolbar 10. At step 1110, lift assist actuators1317 are preferably set to a maximum or high pressure such that the liftassist wheels 1550 (FIG. 15) firmly engage the soil. At step 1115, thewing section actuators 428 are fully retracted to bring wing sections410 in parallel relation with center bar 520. At step 1120, the wingsection actuators 428 are preferably locked in the fully retracted stateusing suitable cylinder locking mechanisms such as those incorporated inthe hydraulic lock-on-retract self-locking cylinders available from PFA,Inc. in Germantown, Wis. At step 1125, the draft bar latch actuators 432are retracted to latch the draft bars 405,415. At step 1130 the wingwheel actuators 1319 are extended such that the wing wheels firmlyengage the soil. At step 1135, the kingpin latch actuators 222 areextended to disengage the kingpin latches 212, freeing the kingpins 512and allowing the rear section 500 to be moved backward relative to themount 200. At step 1140, the wing fold cylinders 424 are extended,folding the wing sections 410 and draft bars 405,415 toward substantialalignment along a direction parallel to the direction of travel. At step1145, the operator may drive the tractor forward to simultaneouslyassist the folding process of step 1140, but the operator may also leavethe tractor in place or simply allow it to roll as needed during step1140. At step 1150, once the wing fold cylinders 424 are fully extendedand the folding frame is in the transport position, the transport latchactuator 416 is preferably retracted to engage transport latch 480,retaining the folding frame in the transport position.

In operation, the toolbar 10 preferably reconfigures from the transportposition to the work position according to a process illustrated in FIG.12. At step 1205, the transport latch actuator 416 is extended todisengage transport latch 480, freeing the wing sections 410 and thedraft bars 405,415 to pivot relative to one another in a substantiallyhorizontal plane. At step 1210, the operator may optionally begin todrive the tractor backward but may also keep the tractor in place orallow the tractor to roll as needed. At step 1215, the wing foldcylinders 424 are retracted, folding the wing sections 41 and draft bars405,415 toward substantial alignment along a direction transverse to thedirection of travel. At step 1220, once the kingpins 512 are situatedwithin kingpin latches 212, the kingpin latch actuators 222 areretracted, engaging the kingpin latches to hold the rear section 500 inplace and retain the folding frame 400 in the work position. At step1225, the wing wheel actuators 1319 are preferably retracted, raisingthe wing wheels off the ground. At step 1230, the draft bar latchactuators 432 are extended to unlatch the draft bars 405,415. A step1235, wing section actuators 428 are unlocked, allowing wing sections410 to pivot relative to center bar 520 in a substantially verticalplane. At step 1245, lift assist actuators 1317 are preferably set to alow pressure. At step 1250, the mount cylinder 230 is extended from itsretracted position, lowering the toolbar 10 into the work position.

Height Control Methods

Where planter row units 1400 (FIG. 14) are used in conjunction withtoolbar 10, it is desirable to maintain a constant height of toolbar 10relative to the soil such that the parallel arms 14 are substantiallyparallel to the ground in order to improve the smoothness of the rowunit ride as the planter traverses the field, thereby improving seedplacement accuracy. In operation, such height control may beaccomplished using the height control system 1350 (FIG. 13) and heightsensors 1360. Using toolbar 10 as an exemplary frame embodiment, theheight of the center bar 520 and wing sections 410 relative to theground may be separately controlled to account for variations in soiltopography.

One such height control method is illustrated in FIG. 18. At step 1805,the height of center bar 520 is determined using height sensor 1360incorporated in a row unit 1400 mounted to the center bar 520. At step1810, the controller 1302 determines whether the center bar height iswithin a desired range. If it is not, at step 1815 the controller 1302commands an adjustment in mount cylinder position tending to bring thecenter bar height within the desired range. For example, in theembodiment illustrated in FIG. 15, if the height of center bar 520 wastoo low relative to the soil, the mount cylinder 230 would preferablyretract in order to raise the center bar. In order to accomplish thisstep, the fluid control system 1330 preferably controls the mountcylinder 230 in a flow control mode (e.g., using a flow control valve1334 incorporated in the fluid control system 1330). Thus the fluidcontrol system 1330 is operable to control the position (i.e., thedegree of extension) of the mount cylinder 230. If the system determinesthat the center bar is at the desired height, then at step 1820 thetoolbar control system maintains the mount cylinder position anddetermines the wing section height at step 1825. As with the center bar,the height of each wing section 410 relative to the ground is preferablydetermined using the signal from a height sensor 1360 incorporated in arow unit on the wing section. At step 1830, the controller 1302determines whether the heights of the wing sections 410 are within adesired range. If they are not, wing section actuators 428 are then usedto adjust the height of wing sections 410 at step 1835. Once the wingsections 410 are within the desired range, the controller 1302 maintainsthe position of wing section actuators 428 at step 1840.

Because the height of row units along each wing section 410 (and to alesser extent along the center bar 520) may vary at any given time,there may exist situations in which the toolbar may be insufficientlyarticulated to bring all instrumented row units (i.e., those havingheight sensors 1360) within the desired height range. Thus according toa modified height control method, a bar section height average isdetermined (e.g., wing section height average at step 1830) by averagingthe height determined for multiple row units along a section. Thesection height is then corrected (e.g., at step 1835) in order to bringthe section height average within a desired range. This method has theadditional advantage of reducing the frequency of height adjustment.

In some embodiments, the method illustrated in FIG. 18 is modified suchthat the center sections and wing sections are controlled independently.One such embodiment is illustrated in FIG. 22, which illustrate a centersection height control loop 2210 for controlling the height of centerbar 520 and an independent wing section height control loop 2220 forcontrolling the height one of the wing sections 410. It should beappreciated that a second wing section control system similar to wingsection control system 2220 preferably controls the height of theopposite wing section 410.

Turning to the center section height control system loop of FIG. 22, thereference 2211 preferably corresponds to a desired center sectionheight, e.g., the desired signal from one or more height sensors 1360associated with one or more row units on the center section. The errorbetween the reference 2211 and a sensor signal 2218, e.g., the actualsignal from one or more height sensors 1360 associated with one or morerow units on the center section, is processed at a signal processingstep 2212 to determine an input signal 2214. The processing step 2212 ispreferably performed by the controller 1302 and preferably comprisesproportional-integral-derivative processing steps known in the art toensure timely correction while avoiding overcorrection. The input signal2214 is commanded to the fluid control system 1330, which introduces acorresponding flow into the system 2216, specifically into the mountcylinder 230 of toolbar 10. The resulting sensor signal 2218 is againcompared to the reference 2211.

Turning to the wing section height control system loop of FIG. 22, thereference 2221 preferably corresponds to a desired wing section height,e.g., the desired signal from one or more height sensors 1360 associatedwith one or more row units on the wing section. The error between thereference 2221 and a sensor signal 2228, e.g., the actual signal fromone or more height sensors 1360 associated with one or more row units onthe wing section, is processed at a signal processing step 2222 todetermine an input signal 2224. The processing step 2222 is preferablyperformed by the controller 1302 and preferably comprisesproportional-integral-derivative processing steps known in the art toensure timely correction while avoiding overcorrection. The input signal2224 is commanded to the fluid control system 1330, which introduces acorresponding flow into the system 2216, specifically into the wingsection actuator 428 of toolbar 10. The resulting sensor signal 2228 isagain compared to the reference 2221.

Because changes to the center section height necessarily change the wingsection height, the processed center section height error is preferably“fed forward” to the wing section height control loop. As illustrated inthe combined control loop 2300 of FIG. 23, a gain 2310 is preferablyapplied to the processed center section height error. The gain 2310preferably corresponds to the difference in diameter between the wingsection actuator 428 and the mount cylinder 230. The gained error isthen preferably subtracted from the processed wing section height errorbefore the wing section actuator flow command is determined. Thus thecombined control loop 2300 determines a wing section actuator flowcommand based in part on the error in the center section height. This“feed-forward” method results in faster system response and avoidsredundant or undesirable commands to the wing section actuators 428. Forexample, if the center section and both wing sections are all 2centimeters higher than desired, the control loop 2300 preferably lowersthe center section without substantially adjusting the position of wingsection actuators 428.

According to another preferred height control method illustrated in FIG.21, the controller 1302 determines all three section height averages atstep 2105, compares all three section height averages to a desired rangeat step 2107, consults a look-up table at step 2110 to determine aprescribed action, and then takes the prescribed action at step 2115.Such a look-up table 2000 is illustrated in FIG. 20. The look-up table2000 includes a set of scenarios 2100 based on the section heightaverage of each section of toolbar 10. In the illustrated lookup table,a section average is marked as “Good” if the row units are at thedesired position relative to the toolbar, “High” if the row units aretoo high relative to the toolbar, and “Low” if the row units are too lowrelative to the toolbar. A preferred action set 2200 corresponds to eachscenario. A stop condition set 2250 preferably corresponds to eachscenario. The controller 1302 determines whether the stop condition hasbeen met at step 2120; once the stop condition has been met, thecontroller stops the prescribed action at step 2125.

The first three scenarios listed in the top three rows of lookup table2000 are schematically illustrated in FIG. 19A-19C, respectively. InFIG. 19A, all three sections of toolbar 10 are too close to the soilsuch that the average height of the row units on each section is higherthan the desired height Hd. Thus the desired toolbar height Hd is bestachieved by retracting the mount cylinder 230 to raise center bar 520 asprescribed in scenario 1 of lookup table 2000. In FIG. 19B, only theright wing section 410-2 is too close to the soil such that the averageheight of the row units on the right wing section is too high. Thus thedesired toolbar height Hd is best achieved by retracting the rightcylinder to raise the right wing section as prescribed in scenario 2 oflookup table 2000. In FIG. 19C, only the center bar 520 is too close tothe soil such that the average height of row units on the center sectionis too high. Thus the desired toolbar height Hd is best achieved byretracting the mount cylinder.

Weight Transfer Methods

In the embodiment of toolbar 10 illustrated in FIG. 15, the weightimposed on the soil during operation is imposed by the lift assistwheels 1550, ground-working tools 1400, and tires 6 of the tractor 5. Inorder to perform ground-working operations such as opening a furrow forplanting seeds, toolbar 10 requires a certain amount of weight toproperly penetrate the soil. However, empirical evidence has shown thatagronomic benefit may result from having the minimum weight possible onthe toolbar due to reduced soil compaction. Moreover, the weight of thetractor 5 on the soil has detrimental agronomic effects whose severitydepends in part on whether the tractor is carried by tires or by tracktreads (which spread out the load on the soil across a larger contactarea). In addition, empirical evidence has shown that the additionalagronomic damage caused by a second soil-compacting wheel pass is less(per applied pound) than that caused by a first pass.

Thus depending on the circumstances, it may be desirable to shift weightfrom the toolbar 10 to the tractor 5 in order to reduce the excessweight between the toolbar and the ground. However, in othercircumstances (e.g., where the toolbar 10 does not have sufficientweight to perform ground-working operation), it may be desirable toshift weight from the tractor 5 to the toolbar.

According to weight transfer methods such as that illustrated in FIG.24, the toolbar control system 1300 maintains a constant pre-determinedpressure in lift assist actuators 1317 when the toolbar is in theplanting configuration. At step 2405, a desired lift assist actuatorpressure is stored in the memory 1309 of the controller 1302. Step 2405may be performed by the manufacturer in programming the controller 1302or may be performed by the operator using the user interface of thecontroller 1302. At step 2410, the controller 1302 preferably confirmswhether the toolbar is in the work position, e.g., using positionsensors 1340 or by determining whether the operator has instructed thetoolbar to assume the work position. At step 2415, the controller 1302determines the pressure in the lift assist actuator 1317. In someembodiments, the controller 1302 determines the lift assist actuatorpressure using the pressure commanded by the fluid control system 1330(e.g., the pressure commanded to a pressure control valve 1332, such asa pressure reducing-relieving valve, incorporated in the fluid controlsystem 1330). In other embodiments, the controller 1302 determines thelift assist pressure using the signal from a pressure sensor 1357associated with the lift assist actuator. As illustrated in FIG. 13, insuch embodiments the pressure sensor 1357 is preferably in electroniccommunication with the controller 1302. At step 2420, the controller1302 determines whether the actual lift assist actuator pressurecorresponds to the desired pressure. If the values do not correspondthen the controller commands an adjustment in lift assist actuatorpressure at step 2425. Once the values correspond then the controllermaintains the lift assist actuator pressure at step 2430.

According to weight transfer methods such as that illustrated in FIG.25, the controller 1302 displays the pressure in lift assist actuators1317 and allows the operator to adjust the pressure in lift assistactuators 1317. At step 2505, the controller 1302 determines the liftassist actuator pressure using either the signal from a pressure sensorassociated with the lift assist actuator or the current command signalused to set the pressure in the lift assist actuator. At step 2510, thecontroller displays the lift assist actuator pressure to the operator.At step 2515, the controller 1302 accepts a pressure command from theoperator, allowing the operator to adjust the commanded lift assistactuator pressure. At step 2520, the controller sets theoperator-commanded pressure in the lift assist actuator either by simplysetting a command signal corresponding to a desired pressure or byadjusting the command signal until a measured pressure (e.g., asreported by pressure sensor 1357) corresponds to the desired pressure.

According to other weight transfer methods, the toolbar control system1300 determines a weight shift representing the weight being transferredbetween the tractor and the toolbar, compares the actual weight shift toa desired weight shift, and adjusts the weight shift to more closelyapproximate the desired weight shift.

One such method is illustrated schematically in FIG. 16. At step 1605,the controller 1302 determines a desired range of pressure in mountcylinder 230. This range is preferably based on multiple factorsincluding the weight, size and configuration of the tractor 5, whetherthe tractor 5 is carried by tires or tracks, and the weight of thetoolbar 10. At step 1610, the controller 1302 obtains the currentpressure in the mount cylinder 230 from the weight transfer sensor 1355.At step 1615, the controller 1302 determines whether the mount cylinderpressure is within the desired range. As best seen in FIG. 15,increasing the pressure in lift assist actuator 1317 tends to shiftweight from the tractor 5 to the toolbar 10. (Saddle 510 is shownschematically in FIG. 15 for clarity, illustrating that the mount 200 ismounted integrally to the center bar 520.) Thus, if the mount cylinderpressure is outside the desired range, then at step 1625 the controlleradjusts the commanded pressure in lift assist actuator 1317 in order toproduce a desired change in the mount cylinder pressure. (Lift assistactuators 1317 are preferably pressure-controlled by the fluid controlsystem 1330, e.g., using a pressure control valves 1332 such as pressurereducing-relieving valves, such that the controller 1302 may set andmaintain a desired pressure in the lift assist cylinders by modifyingthe fluid control system.) Once the mount cylinder pressure is withinthe desired range, the controller 1302 maintains the lift assistcylinder pressure at step 1620.

According to another method of using toolbar 10, the weight shiftbetween the tractor 5 and toolbar 10 may be modified based on thepressure in tool downforce actuators 32. The pressure in tool downforceactuators 32 indicates the weight being added to or removed from thetoolbar 10 by the ground-working tools 10. When the tool downforce beingtaken from the toolbar 10 exceeds a predetermined range, it may bedesirable to shift weight from the tractor 5 onto the toolbar to assistin providing sufficient downforce for ground-working operations.Likewise, when the tool weight being added to the toolbar 10 exceeds apredetermined range, it may be desirable to shift weight from thetoolbar to the tractor 5 to assist in flotation of the ground-workingtools and to minimize soil compaction.

Such a method is illustrated in FIG. 17. At step 1705, the controller1302 determines a desired range of pressure in tool downforce actuators32. At step 1710, the controller 1302 obtains the current pressurecommanded to the tool downforce actuators 32 by the control system 1300.At step 1715, the controller 1302 determines whether the tool downforcepressure is within the desired range. If the tool downforce pressure isoutside the desired range, then at step 1725 the controller adjusts thecommanded pressure in lift assist actuator 1317 in order to produce adesired change in the mount cylinder pressure. Once the tool downforcepressure is within the desired range, the controller 1302 maintains thelift assist cylinder pressure at step 1720.

The method described above with respect to FIG. 17 may preferably beused with a downforce control system such as that described inApplicant's co-pending U.S. application Ser. No. 13/014,546, thedisclosure of which is hereby incorporated herein in its entirety byreference. Using such a system, the supplemental downforce applied bytool downforce actuators 32 is adjusted automatically in response to arow unit downforce measurement in order to maintain the minimumdownforce necessary on each row unit 1400.

The foregoing description is presented to enable one of ordinary skillin the art to make and use the invention and is provided in the contextof a patent application and its requirements. Various modifications tothe preferred embodiment of the apparatus, and the general principlesand features of the system and methods described herein will be readilyapparent to those of skill in the art. Thus, the present invention isnot to be limited to the embodiments of the apparatus, system andmethods described above and illustrated in the drawing figures, but isto be accorded the widest scope consistent with the spirit and scope ofthe appended claims.

The invention claimed is:
 1. A control system for an agriculturaltoolbar drawn across a ground surface by a tractor, comprising: a wheelcoupled to the toolbar and engaging the ground surface; an actuatorhaving an actuator pressure, said actuator being coupled to the toolbar,said actuator being disposed to modify a ground force between said wheeland the ground surface, said ground force being related to said actuatorpressure; a fluid control system, said fluid control system being influid communication with said actuator, said fluid control system beingoperable to control said actuator pressure; and a controller inelectrical communication with said fluid control system, wherein saidcontroller is operable to send a command signal to the fluid controlsystem, said command signal corresponding to a desired pressure, andwherein said fluid control system is operable to modify said actuatorpressure in response to said command signal such that said actuatorpressure corresponds to said desired pressure, and wherein said fluidcontrol system is operable to maintain said actuator pressure at saiddesired pressure.
 2. The control system of claim 1, wherein the toolbarhas a work position and a transport position, and wherein said wheelsubstantially supports a weight of the toolbar in the transportposition.
 3. The control system of claim 1, further including anelectronic display in electrical communication with said controller,said electronic display being mounted in an operator station of thetractor, said electronic display being operable to display said desiredpressure to an operator, said electronic display being operable toreceive an actuator pressure command from said operator and to set saidactuator pressure command.
 4. The control system of claim 1, furtherincluding a weight transfer sensor in electrical communication with saidcontroller, said weight transfer sensor operable to send a weighttransfer signal to said controller.
 5. The control system of claim 4,wherein said controller stores a desired weight transfer signal value,wherein said controller is operable to modify said desired pressure suchthat said weight transfer signal becomes closer to said desired weighttransfer signal value.
 6. The control system of claim 5, furtherincluding a weight transfer actuator, said weight transfer actuatorbeing operable to transfer weight between the tractor and the toolbar,said weight transfer actuator having a weight transfer actuatorpressure, wherein said weight transfer sensor comprises a pressuresensor, wherein said weight transfer signal comprises a signal relatedto said weight transfer actuator pressure.
 7. The control system ofclaim 6, wherein said weight transfer actuator is in fluid communicationwith said fluid control system, and wherein said fluid control system isoperable to control a position of said weight transfer actuator.
 8. Thecontrol system of claim 7, wherein said position of said weight transferactuator is related to a height of the toolbar relative to the tractor.9. The control system of claim 8, wherein the toolbar includes a wingsection and a center section, said wing section being pivotally mountedto said center section for pivoting relative to said center sectionabout a generally horizontal axis, and further including a wing sectionactuator operable to pivot said wing section about said generallyhorizontal axis, wherein said wing section actuator is in fluidcommunication with said fluid control system, wherein said fluid controlsystem is operable to control a position of said wing section actuator.10. The control system of claim 5, wherein said controller stores adesired weight transfer value, further comprising an electronic displayin electrical communication with said controller, said electronicdisplay being mounted in an operator station of the tractor, saidelectronic display being operable to display a value corresponding tosaid weight transfer signal to an operator, said electronic displaybeing operable to receive a weight transfer command from said operatorand modify said desired weight transfer signal value based on saidweight transfer command.
 11. A method of controlling an agriculturaltoolbar drawn across a ground surface by a tractor, comprising:reconfiguring the toolbar from a transport position to a work position;sending a command signal corresponding to a desired ground force betweena ground-engaging wheel pivotally coupled to said toolbar and the groundsurface; modifying an actuator pressure in a weight transfer actuatorsuch that said ground force corresponds to said desired ground force;and maintaining said modified actuator pressure such that said groundforce is maintained at said desired ground force.
 12. The method ofclaim 11, further comprising: reconfiguring the toolbar from said workposition to said transport position; and supporting a portion of theweight of said toolbar with said ground-engaging wheel in said transportposition.
 13. The method of claim 11, further comprising: displaying avalue related to said ground force to an operator; receiving an inputcorresponding to said command signal from said operator; and modifyingsaid ground force based on said input.
 14. The method of claim 11,further comprising: measuring a weight transfer value.
 15. The method ofclaim 14, further comprising: storing a desired weight transfer value;and modifying said actuator pressure such that said weight transfervalue becomes closer to said desired weight transfer value.
 16. Themethod of claim 15, further comprising: transferring weight between thetractor and the toolbar using said weight transfer actuator, whereinsaid step of measuring said weight transfer value is accomplished bymeasuring said actuator pressure in said weight transfer actuator. 17.The method of claim 16, further comprising: controlling a degree ofextension of said weight transfer actuator.
 18. The method of claim 17,wherein said degree of extension of said weight transfer actuator isrelated to a height of the toolbar relative to the tractor.
 19. Themethod of claim 18, further comprising: modifying an angular position ofa wing section of said toolbar.
 20. The method of claim 15, furthercomprising: displaying a value corresponding to said weight transfervalue to an operator; receiving a command from said operator; andmodifying said weight transfer value based on said command.
 21. Acontrol system for an agricultural toolbar drawn across a ground surfaceby a tractor, comprising: a wheel coupled to the toolbar and engagingthe ground surface; an actuator having a net actuator pressure, saidactuator being coupled to the toolbar, said actuator being disposed tomodify a ground force between said wheel and the ground surface, saidground force being related to said net actuator pressure; a fluidcontrol system, said fluid control system being in fluid communicationwith said actuator, said fluid control system being operable to bringsaid actuator pressure to a desired actuator pressure; an electroniccontrol system in electronic communication with said pressure controlvalve, wherein said electronic control system is operable to modify saiddesired actuator pressure and; a weight transfer sensor in electroniccommunication with said electronic control system, said weight transfersensor operable to send a weight transfer signal to said electroniccontrol system.
 22. The control system of claim 21, wherein saidelectronic control system stores a desired weight transfer signal value,wherein said electronic control system is operable to modify saiddesired actuator pressure such that said weight transfer signal becomescloser to said desired weight transfer signal value.
 23. The controlsystem of claim 22, further including a weight transfer actuator, saidweight transfer actuator being operable to transfer weight between thetractor and the toolbar, said weight transfer actuator having a weighttransfer actuator pressure, wherein said weight transfer sensorcomprises a pressure sensor, wherein said weight transfer signalcomprises a signal related to said weight transfer actuator pressure.24. The control system of claim 23, wherein said weight transferactuator is in fluid communication with said fluid control system, andwherein said fluid control system is operable to control a position ofsaid weight transfer actuator.
 25. The control system of claim 24,wherein said position of said weight transfer actuator is related to aheight of the toolbar relative to the tractor.
 26. The control system ofclaim 25, wherein the toolbar includes a wing section and a centersection, said wing section being pivotally mounted to said centersection for pivoting relative to said center section about a generallyhorizontal axis, and further including a wing section actuator operableto pivot said wing section about said generally horizontal axis, whereinsaid wing section actuator is in fluid communication with said fluidcontrol system, wherein said fluid control system is operable to controla position of said wing section actuator.
 27. The control system ofclaim 22, wherein said electronic control system stores a desired weighttransfer value, further comprising an electronic display in electroniccommunication with said electronic control system, said electronicdisplay being mounted in an operator station of the tractor, saidelectronic display being operable to display a value corresponding tosaid weight transfer signal to an operator, said electronic displaybeing operable to receive a weight transfer command from said operatorand modify said desired weight transfer signal value based on saidweight transfer command.
 28. A method of controlling an agriculturaltoolbar drawn across a ground surface by a tractor, comprising:reconfiguring the toolbar from a transport position to a work position;modifying-a ground force between a ground-engaging wheel pivotallycoupled to said toolbar and the ground surface; and measuring a weighttransfer value storing a desired weight transfer value; and, modifyingsaid ground force such that said weight transfer value becomes closer tosaid desired weight transfer value.
 29. The method of claim 28, furthercomprising: transferring weight between the tractor and the toolbarusing a weight transfer actuator, wherein said step of measuring saidweight transfer value is accomplished by measuring a pressure in saidweight transfer actuator.
 30. The method of claim 29, furthercomprising: controlling a degree of extension of said weight transferactuator.
 31. The method of claim 30, wherein said degree of extensionof said weight transfer actuator is related to a height of the toolbarrelative to the tractor.
 32. The method of claim 31, further comprising:modifying an angular position of a wing section of said toolbar.
 33. Themethod of claim 28, further comprising: displaying a value correspondingto said weight transfer value to an operator; receiving a command fromsaid operator; and modifying said weight transfer value based on saidcommand.